The researchers suspected that keanumycins could also kill fungi, as these resemble amoebas in certain characteristics. This assumption was confirmed together with the Research Centre for Horticultural Crops at the University of Applied Sciences Erfurt. There, Keanumycin was shownto be effective against grey mould rot on hydrangea leaves. In this case, culture fluid that no longer contained bacterial cells was sufficient to significantly inhibit the growth of the fungus.
"Theoretically, the keanumycin-containing supernatant from Pseudomonas cultures could be used directly for plants," says Götze. Further testing will be carried out together with the colleagues in Erfurt. Keanumycin is biodegradable, so no permanent residues should form in the soil. This means that the natural product has the potential to become an environmentally friendly alternative to chemical pesticides.
Fungal diseases such as Botrytis cinerea, which causes grey mould rot, cause immense harvest losses in fruit and vegetable cultivation every year. More than 200 different types of fruit and vegetables are affected, especially strawberries and unripe grapes.
Possible applications in humans
"In addition, we tested the isolated substance against various fungi that infect humans. We found that it strongly inhibits the pathogenic fungus Candida albicans, among others," says Götze.
Instead of plants, Keanumycin could therefore possibly also be used in humans. According to the tests conducted so far, the natural product is not highly toxic for human cells and is already effective against fungi in very low concentrations. This makes it a good candidate for the pharmaceutical development of new antimycotics. These are also urgently needed, as there are very few drugs against fungal infections on the market.
The work was supported by the Werner Siemens Foundation, the Leibniz Association and the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) as part of the Balance of the Microverse Cluster of Excellence, and funded by the Dr. Illing Foundation.
The study was highlighted by Nature in a "News & Views" article.
Original publication
Götze S, Vij R, Burow K, Thome N, Urbat L, Schlosser N, Pflanze S, Müller R, Hänsch VG, Schlabach K, Fazlikhani L, Walther G, Dahse HM, Regestein L, Brunke S, Hube B, Hertweck C, Franken P, Stallforth P (2023). Ecological niche-inspired genome mining leads to the discovery of crop-protecting nonribosomal lipopeptides featuring a transient amino acid building block. J Am Chem Soc, doi: 10.1021/jacs.2c11107